[ILUG] Mulithost SCSI Question.

[Colin Whittaker]

Kenn Humborg stated the following on Thu, Jun 22, 2000 at 06:19:04PM +0100 :
> > Say I had 2 hosts A & B, both have a scsi card ( id's 7 & 6 repectivly )
> > and a scsi disk ( id 0 ).
> > 
> > This disk has a single filesystem on it.
> > 
> > Can host A mount the fs rw and host B mount it ro.
> 
> Not really.  Host A will have a consistent view of the
> fs, but Host B won't.  It won't know when to invalidate stuff 
> that it's cached.  Host A could serve the filesystem over
> NFS, thus ensuring that all read access goes through Host A's
> cache.
> 
> Right now, your best bet is probably the heartbeat project
> at http://linux-ha.org.  Every so often the mailing list 
> heads off into a discussion on shared disk handling, so
> there is probably some info on these issues there.
> 
> In the long term, the Linux Cluster Cabal's VMS-like 
> clustering will be the way to go.
> 
> > If host A goes away for some reason ( crash etc ) can host B remount the
> > fs rw or will much stuff break.
> 
> You'll need to use a journalling filesystem or you'll spend
> ages fscking before you can safely remount.

This drbd[0] thingy coupled with say reiserfs could have promise.

[0] http://www.complang.tuwien.ac.at/reisner/drbd
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